yeah you can, it’s just sometimes easier to pour the gaiwan quickly into a large pitcher than tiny cups, also helpful in your case where the cups are smaller than the gaiwan, brewing you like 2-3 servings at a time. Give it a try and see, if you find you need one the small glass ones are quite cheap, or you could even substitute a glass measuring cup or whatever else you have lying around in the mean time. You don’t necessarily need something purpose made from a tea vendor, just grab any random thing off the shelf at walmart or out of your cabinet, anything will work, glass measuring cup, little coffee creamer pitcher, another small tea pot, anything really. (you’ll probably slightly overflow those 2 50ml cups with a 130ml gawian, unless you’re really packing it with tea)

I’d second what sansnipple said. It’s just nice to have a pitcher to pour it all into instead of trying to pour equally between two+ cups.
Honestly I don’t have an actual pitcher like you can get from vendors selling gaiwans and teaware. I’ve seen plenty of nice little pitchers at Goodwill/Savers that I think are supposed to be creamer or gravy pitchers, but would work nicely for tea. That’s what I use though I had to go through one or two before I found one I liked since they turned out to have a rotten pours/too big/etc. I just recently got a little glass teapot that doubles well as a pitcher. Though I’m still on the lookout for the perfect one for my set. Lol.
I would recommend that if you do end up using a pitcher to get a strainer to use with it. You can find them on ebay and I think some tea vendors sell them too. You can also use the mesh strainers that come with some teapots. Even half of a mesh tea ball in a pinch until you get something better.

I bought a pitcher for cream and use that, however pitchers are pretty cheap. Also it’s best to use one as the tea could be more flavored at the end of the pour, so one cup could be strong tasting, the other one light.

But yeah, I use my strainer often, even if I’m not using a pitcher, I just plop it over the cup I’m drinking out of (that’s not a teenyy 50ml one) and pour the whole gaiwan steep into that.
I got mine from Mandala, but many places with gaiwans sell them. This style fits perfectly over a pitcher http://shopmandalatea.com/stainless-fine-mesh-filter.html

I don’t use a pitcher and just pour into my cups, but that is mostly laziness and wanting to have less dirty dishes. Some impatience in there too. If you don’t have any of the other ideas suggested you could use a liquid measuring cup. That is what we use for gravy, hah!

As sansnipple said, it’s more convenient to pour the brewed liquor into the pitcher than cups. when you sipping the first steep,then you can ready to brew the next steep. Meanwhile, if you are sharing tea with your friends, it’s better to make the same density and taste throughout before serving the tea to your friends.

However, it’s up to you, if you feel it’s easy to pour the liquor into cups, you can use gaiwan without a pitcher.

It takes some finesse to pour evenly with a gaiwan into multiple small tasting cups (even more so than with a pot), though it’s a skill worth learning. If you are careful about not making too big a gap when you tip the lid, it will be easier, and you’ll need to go around so that the volume and concentration are more or less even between the cups.

The fair cup is a fairly recent refinement, and as others have mentioned, it just makes it easier, especially when serving a lot of people.

Biggest advantage of skipping the fair cup is probably that you’ll lose a bit less heat.